anagram compressor: https://repl.it/@skiano/SympatheticWarpedRaptors-2

anagram-compressor.js

// A compressor for anagram puzzle data
// because we know all the solutions to anagram puzzles
// have a very small number of characters, we can compress
// the data more strategically
//
// given a list of letters, this creates an encode and decode function
//
// for example
// given the letters:
//    'NCEHITK'
// and the list of words:
//    ['KITCHEN', 'KITCHENETTE', 'THICKEN', 'CENT', 'CHIN', 'CINE', 'HENT', 'HINT', 'INCH', 'KEEN', 'KENT', 'KINE', 'KNEE', 'KNIT']
// the compressed data looks like this:
//    ɽͪN,ɽͪɕȜ,Ș͚N,ͮT,ͨN,͞E,˾T,ˮT,ʫH,ʒN,ʎT,ɾE,ɲE,ɰT

const createAnagramCompressor = (letters, a, b, c, v, k2, k3) => {
  const sorted = letters.split('').sort()
  const len = sorted.length
  const map = {}
  const reverseMap = {}
  
  let i = 500 // just a charcode well out of range

  a = len
  while(a--) {
    b = len
    while(b--) {
      k2 = sorted[a] + sorted[b]
      v = String.fromCharCode(i)

      map[k2] = v
      reverseMap[v] = k2

      c = len
      while(i++, c--) {

        k3 = k2 + sorted[c]
        v = String.fromCharCode(i)

        map[k3] = v
        reverseMap[v] = k3
      }
    }
  }

  const encodeWord = (word, final, i) => {
    final = ''
    i = 0
    while (i < word.length) {
      const chunk = word.substr(i, 3)
      final += map[chunk] || chunk
      i += 3
    }
    return final
  }
  
  const decodeWord = (word, i) => {
    final = ''
    i = 0
    while(i < word.length) {
      const k = word.charAt(i)
      final += reverseMap[k] || k
      i++
    }
    return final
  }

  return {
    encode: (words) => words.map(encodeWord).join(),
    decode: (str) => str.split(',').map(decodeWord),
  }
}

const letters = 'NCEHITK'
const solutions = ['KITCHEN', 'KITCHENETTE', 'THICKEN', 'CENT', 'CHIN', 'CINE', 'HENT', 'HINT', 'INCH', 'KEEN', 'KENT', 'KINE', 'KNEE', 'KNIT', 'NECK', 'NICE', 'NICK', 'NINE', 'NITE', 'TEEN', 'TENT', 'TEIN', 'THEN', 'THIN', 'TINE', 'TINT', 'CHICKEN', 'CHINK', 'CINCH', 'ENTENTE', 'ENTICE', 'ETHNIC', 'HEINIE', 'HENCE', 'INCITE', 'INNIE', 'INTENT', 'KINETIC',  'KITTEN','NECKTIE', 'NICHE', 'NIECE', 'NINETEEN', 'NINETEENTH', 'NINETIETH', 'NINTH', 'TENET', 'TENTH', 'THENCE', 'THINE', 'THINK', 'TINCT']

const { encode, decode } = createAnagramCompressor(letters)
const encoded = encode(solutions)
const decoded = decode(encoded)

console.log(`
  compressed anagram list:
  ${encoded}
  
  ---

  base64          ${btoa(JSON.stringify(solutions)).length}
  JSON.stringify  ${JSON.stringify(solutions).length}
  custom          ${encoded.length}
  
  matches         ${JSON.stringify(decoded) === JSON.stringify(solutions)}
`)